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Stateful firewall-enabled software-defined network with distributed controllers: A network performance study

INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS 2019年第17期32卷

作者： Prabakaran, Senthil Ramar, Ramalakshmi Kalasalingam Acad Res & Educ Dept Elect & Commun Engn Anandnagar 626126 Tamil Nadu India Kalasalingam Acad Res & Educ Dept Comp Sci & Engn Anandnagar 626126 Tamil Nadu India

Software-defined network (SDN) is constructed by decoupling the control and data plane from the forwarding devices. The control plane operations are managed by centralized or distributed controllers, and the data plane operation is managed by respective forwarding devices. SDN provides an easy and efficient management solutions for software-programmed consolidated middlebox in virtual machines. Additionally, SDN with centralized controller faces complications like scalability, network bottle neck, and single point failure. In this study, a stateful inspection firewall acts as a middlebox in distributed SDN-controlled network. The controller is programmed with a failure detection and recovery mechanism to provide reliability and redundancy and enhance the overall performance of the network. The objective of stateful firewall on SDN architecture is to secure the network by monitoring the current connections and maintain its state information until the connection is active. In this paper, the performance of firewall-enabled SDN with centralized and distributed controllers are measured, compared, and analyzed. The experiments are done using POX controller, and the results are verified by Mininet network emulation tool. The results show that the stateful firewall-enabled SDN with distributed controller network improves the security, reliability, availability, and overall performance of the network. In the proposed SDN, average network throughput is improved by 43%, average network delay is reduced by 4%, average channel utilization is increased by 40%, average network overhead is reduced by 26%, and average network response time is reduced by 23%.

关键词： distributed controller middlebox OpenFlow SDN software-defined network stateful firewall

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Clustering approach to model order reduction of power networks with distributed controllers

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ADVANCES IN COMPUTATIONAL MATHEMATICS 2018年第6期44卷 1917-1939页

作者： Cheng, Xiaodong Scherpen, Jacquelien M. A. Univ Groningen Fac Sci & Engn Jan C Willems Ctr Syst & Control Nijenborgh 4 NL-9747 AG Groningen Netherlands

This paper considers the network structure preserving model reduction of power networks with distributed controllers. The studied system and controller are modeled as second-order and first-order ordinary differential equations, which are coupled to a closed-loop model for analyzing the dissimilarities of the power units. By transfer functions, we characterize the behavior of each node (generator or load) in the power network and define a novel notion of dissimilarity between two nodes by the H-2-norm of the transfer function deviation. Then, the reduction methodology is developed based on separately clustering the generators and loads according to their behavior dissimilarities. The characteristic matrix of the resulting clustering is adopted for the Galerkin projection to derive explicit reduced-order power models and controllers. Finally, we illustrate the proposed method by the IEEE 30-bus system example.

关键词： Power network distributed controller Model order reduction Hierarchical clustering

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Network-based distributed direct load control guaranteeing fair welfare maximisation

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IET CONTROL THEORY AND APPLICATIONS 2019年第17期13卷 2959-2968页

作者： Sakurama, Kazunori Ahn, Hyo-sung Kyoto Univ Grad Sch Informat Sakyo Ku Yoshida Honmachi Kyoto 6068501 Japan Gwangju Inst Sci & Technol Sch Mech Engn 123 Cheomdan Gwagiro Gwangju 500712 South Korea

This study examines a distributed direct load control (DLC) problem for maximising customer welfare in a power system for the network communication of energy management controllers (EMCs). A model is first built to describe the dynamics and communication intervals of the EMCs with a distributed and uniform controller. The controller conditions are then derived to stabilise the system and to converge the power imbalance to zero at an assigned rate. The control condition that maximises customer welfare is then found. Furthermore, an optimal controller that maximises customer welfare over a given network communication is proposed, and the performance degradation caused by distributed management is evaluated. This study reveals that even though moving from a centralised to a distributed DLC can degrade customer welfare, this degradation can be reduced by considering consumer properties and network topologies of the EMCs. Numerical examples with real consumption data are also presented to demonstrate the effectiveness of the proposed method.

关键词： telecommunication network topology distributed power generation energy management systems optimisation optimal control power distribution control load regulation optimal controller customer welfare given network communication distributed management distributed DLC network topologies EMCs network-based fair welfare maximisation distributed direct load control problem power system energy management controllers dynamics communication intervals distributed controller uniform controller controller conditions power imbalance control condition

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A distributed Control Technique for the Multilevel Cascaded Converter

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IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS 2019年第2期55卷 1649-1657页

作者： Wu, Ping-Heng Su, Yu-Chen Shie, J. -L. Cheng, Po-Tai Natl Tsing Hua Univ Dept Elect Engn Ctr Adv Power Technol Hsinchu 30013 Taiwan Taiwan Power Co Taipei 10016 Taiwan

In recent years, the modular multilevel cascaded converters (MMCCs) have attracted interest for potential applications in utility-scale photovoltaic and battery energy storage systems. However, the large numbers of cascaded modules increase the difficulty of implementation in a centralized control architecture. This paper presents a distributed control technique for three-phase MMCCs, which can significantly reduce complexity and increases the flexibility to expand the system. In addition, reference voltage analysis is performed to better understand the operation of the proposed method. Experimental results carried out on a seven-level star-connected cascaded converter are included to validate the proposed approach.

关键词： DC capacitor voltages balancing control distributed controller low voltage ride through (LVRT) modular multilevel cascaded converter (MMCC) utility-scale photovoltaic system

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distributed Robust Global Containment Control of Second-Order Multiagent Systems With Input Saturation

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IEEE TRANSACTIONS ON CONTROL OF NETWORK SYSTEMS 2019年第4期6卷 1426-1437页

作者： Fu, Junjie Wan, Ying Wen, Guanghui Huang, Tingwen Southeast Univ Sch Math Dept Syst Sci Nanjing 211189 Peoples R China RMIT Univ Sch Engn Melbourne Vic 3001 Australia Texas A&M Univ Qatar Doha 23874 Qatar

In this paper, we study the robust global containment control problem for second-order multiagent systems with bounded input disturbances subject to input saturation under general directed communication graphs. Two types of distributed controllers based on novel sliding mode control ideas are respectively proposed to solve the globally asymptotic containment problem for multiagent systems with static leaders and the practical containment problem for the case with dynamic leaders subject to unknown control inputs. One distinctive feature of the proposed controllers is that only local velocity measurements, relative position, and velocity measurements are involved in designing the controllers, which thus effectively reduces the information transmission burden among the agents for real-time implementation. Another favorable property of the designed controllers is that the global information such as the spectrum of the graph Laplacian matrix is not required in designing these controllers under general directed communication graphs. Simulations on containment control of multiple quadrotors are performed to illustrate the effectiveness of the proposed containment controllers.

关键词： Containment control directed graph distributed controller input saturation networked multiagent system

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A Dynamic Load Balancing Mechanism for distributed controllers in Software-Defined Networking 10

A Dynamic Load Balancing Mechanism for Distributed Controlle...

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10th International Conference on Measuring Technology and Mechatronics Automation (ICMTMA)

作者： Lan, Wenjing Li, Fangmin Liu, Xinhua Qiu, Yiwen Wuhan Univ Technol Sch Informat Engn Wuhan 430070 Hubei Peoples R China Wuhan Univ Technol Key Lab Fiber Opt Sensing Technol & Informat Proc Minist Educ Wuhan 430070 Hubei Peoples R China

ISBN: (纸本)9781538651148

In recent years, distributed controllers have been designed that the whole network has been divided into several domains with multiple physically distributed but logically centralized controllers to achieve a better performance in both availability and scalability Software-Defined Networking (SDN). However, such distributed architecture is challenged by uneven load distribution among controllers due to the static switch-controller mapping. This paper presents a dynamic and adaptive load balancing mechanism based on a hierarchical control plane for distributed controllers in SDN. We estimate the aggregate load of a controller from the aspect of controller factor and switch factor. Based on load status on each controller, the proposed mechanism can dynamically shift the load from the heavily-loaded controller to the lightly-loaded one via switch migration. Furthermore, by using an adaptive load collection algorithm, the frequency of load information notification is significantly reduced in comparison with existing approaches. The simulation results indicate that the proposed strategy can balance the load of control plane dynamically and increase the throughput of distributed controllers.

关键词： Software-Defined Networking (SDN) OpenFlow Load Balancing distributed controller

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Hybrid position/force output feedback second-order sliding mode control for a prototype of an active orthosis used in back-assisted mobilization

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MEDICAL & BIOLOGICAL ENGINEERING & COMPUTING 2019年第9期57卷 1843-1860页

作者： Ballesteros-Escamilla, M. Cruz-Ortiz, D. Salgado, I. Chairez, I. Inst Politecn Nacl UPIBI Mexico City DF Mexico Inst Politecn Nacl CIDETEC Mexico City DF Mexico

This article shows the design of a robust second-order sliding mode controller to solve the trajectory tracking problem of an active orthosis for assisting back physiotherapies. The orthosis was designed in agreement with morphological dimensions and its articulations distribution followed the same designing rules. The orthosis has six articulated arms attached to an articulated column. The orthosis was fully instrumented with actuators and position sensors at each articulation. The controller implemented a class of hybrid/position controller depending on the relative force exerted by the patient and the orthosis movement. The position information provided by each articulation was supplied to a distributed super-twisting differentiator to recover the corresponding angular velocity. A set of twisting controllers was implemented to regulate the position of the robot in agreement to predefined reference trajectories. Reference trajectories were obtained from a biomechanical-based analysis. The hybrid tracking control problem solved the automation of the assisted therapy to the patient, including the force feedback. The performance of the orthosis was tested with different dummy bodies with different resistance. The robust output feedback controller successfully tracked the reference trajectories despite the material of the dummy used during the testing. The orthosis was evaluated with two volunteers using a simple reference trajectory.

关键词： Back rehabilitation Active orthosis distributed controller Super-twisting differentiator Twisting controller

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Reducing Inconsistency between Software-Defined Networking controllers 5

Reducing Inconsistency between Software-Defined Networking C...

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5th IEEE Conference on Network Softwarization (IEEE NetSoft) / 2nd International Workshop on Advances in Slicing for Softwarized Infrastructures (S4SI)

作者： Tsukuda, Yusaku Kosugi, Masaru Shiomoto, Kohei Morita, Tatsuya Hayashi, Tsunemasa Tokyo City Univ Grad Sch Engn Setagaya Ku 1-28-1 Tamazutsumi Tokyo 1588557 Japan Bosco Technol Inc Tokyo Japan

ISBN: (纸本)9781538693766

In distributed SDN, each controller builds the "global network view" by obtaining missing pieces of global network view from other controllers. All SDN controllers need to maintain consistent view of global network in order to make a correct routing decision. An inconsistent global network view may result in incorrect routing decision a switch. In order to achieve correct routing decision while keeping low latency and high throughput of controller, we need to avoid inter-controller communication overhead at the time of flow setup. In order to do so, we need to make an assignment of switches to controllers such that routing decision on each flow can be made by as small number of controllers as possible. In order to achieve such assignment of switches to controllers, we propose a controller placement model based on traffic locality. We identify a cluster of switches such that fair amount of traffic flow remains inside the cluster and assign the switches belonging to the cluster to the same controller. Thereby the inconsistency between controllers has less impact on the accuracy of controllers routing decision for the traffic flow because the controller is like to have all necessary information on the network resource to calculate the route for the traffic flow. In order to make such clusters of switches, we employ Infinite Relational Model (IRM), a nonparametric Bayesian model that discovers relational structure in data sets as a set of clusters. Simulation results show that our proposed method reduces the inconsistent probability that controllers need to update a global network view.

关键词： SDN Logically Centralized distributed controller Eventually Consistent controller Placement Problem

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distributed Power Sharing Control of The Grid-connected AC Microgrid 5th

Distributed Power Sharing Control of The Grid-connected AC M...

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5th IFAC Symposium on Telematics Applications (TA)

作者： Tang, Qing Bai, Handong Jiang, Huidi Southwest Jiaotong Univ Sch Elect Engn Chengdu 611756 Sichuan Peoples R China

This paper considers a power sharing problem of a grid-connected AC microgrid which consists of multiple dispatchable distributed generators. The microgrid is modeled by a multiagent system and the power sharing problem is formulated as a tracking issue of leader-follower system. Simulations are presented to demonstrate the effectiveness of the proposed control scheme.

关键词： distributed controller Grid-connected AC Microgrid Power Sharing Multiagent Systems

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distributed Finite-Time Coordination Control system for Economical Operation of Islanded DC Microgrids 22

Distributed Finite-Time Coordination Control system for Econ...

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22nd International Conference on Electrical Machines and Systems (ICEMS)

作者： Zaery, Mohamed Wang, Panbao Wang, Wei Xu, Dianguo Harbin Inst Technol Dept Elect Engn Harbin 150001 Peoples R China Aswan Univ Dept Elect Engn Fac Engn Aswan 81542 Egypt

ISBN: (纸本)9781728133980

The operation of standalone DC microgrid (MG) with high penetration level of renewable energy sources (RESs) be more complicated because of MG's low inertia and frequent operating conditions. This paper presents a fully distributed controller to ensure minimal total generation cost (TGC) for autonomous DC MG in a finite time manner. It is implemented by using a distributed finite-time consensus scheme which equalizes the incremental costs (ICs) of all sources to accomplish MG's optimal operation facilitating the balance between generations and demands simultaneously by restoring MG's average voltage within a finite settling time. The proposed controller guarantees an enhanced performance with faster convergence over the conventional distributed secondary controller with a reduced overshoots which is vital for critical loads. The developed control scheme is simulated to testify its effectiveness under different loadings and its resiliency against link-failure and the capability of plug and play is proved.

关键词： DC MGs distributed controller Finite-time protocol Economic operation

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